This invention relates to a curable resin composition comprising a mixture and/or a preliminary reaction product of (a) a polyfunctional cyanate ester, a prepolymer of the cyanate ester or a coprepolymer of the cyanate ester and an amine (sometimes hereinunder referred to as component (a)), and (b) polyamideimide resin (sometimes hereinunder referred to as component (b)) and also relates to a curable resin composition comprising a mixture and/or a preliminary reaction product of (a) a polyfunctional cyanate ester, a prepolymer of the cyanate ester or a coprepolymer of the cyanate ester and an amine, (b) a polyamideimide resin and (c) a polyfunctional maleimide, a prepolymer of the maleimide or a coprepolymer of the maleimide and an amine (sometimes hereinunder referred to as component (c)). Cured resin obtained by curing each of the resin compositions has excellent flex cracking-resistance, water resistance, heat-resistance and chemical resistance.
In the prior art, the coating obtained from a composition containing a polyfunctional cyanate ester and a polyfunctional maleimide has low flex cracking-resistance. The coating obtained from a polyamideimide resin has low water resistance and low chemical resistance.